I loved it, keep up the good work.
I suggest for the next game if it is a sequel, maybe give us some option to start out from where our latest save is.
Also you could maybe create some system where you can also upgrade the guns(power, ammo capacity, accuracy ect.)
One more quick thought, you may be able to incorporate some way to upgrade the states of your survivors that you choose to help fight with you.
Great Game, I sincerely Enjoyed it!